In industries such as the automobile industry, it is often necessary to seal or block certain defined spaces, such as the within pillars or other structural support members of an automobile body. When such pillars or support members are hollow, for example, they may provide a pathway for air or liquid to travel through or into the automobile body. This is undesirable as such pathways or spaces increase the amount of noise within the automobile interior and provide areas for water from rain or car washes to collect. It has been a regular practice to attach expandable gaskets or baffles within these areas of the automobile body structure. Expandable gaskets or baffles have been formed of a rigid steel or plastic support structure connected to an expandable material, such as an expandable rubber compound. Many expandable rubber or polymer compounds exist that expand into a closed cell foam under applied heat, such as during the paint baking process of the automobile body. These materials are well known in the automobile industry and related industries. They are generally capable of being formed into various shapes by injection or extrusion molding techniques. The foam is often used to fill the defined space within the automobile frame thereby blocking a potential pathway for air or liquid.
Typical expandable gaskets or baffles have been constructed with either a plastic or metal plate structure mechanically fastened to the expandable material with clips or press fit pins extending from the support plate. For example, steel plates with a plurality of apertures have been used as gasket or baffle support structures. For a baffle, two steel plates may sandwich a flat piece of expandable material. For a gasket, the expandable rubber may be attached to one side of a support plate. In these typical examples, the attachment is made using metal or plastic clips. Apertures have been provided in steel plates to reduce the weight of the plate and to provide a limited pathway for the expandable rubber to foam through to the opposite side of the plate. The plate may further include fasteners for mounting the gasket or baffle to a desired portion of the automobile body structure. These fasteners have been separate fasteners or integral fasteners, such as bends in a steel plate formed as a clip. A major drawback to these products is the relatively high manufacturing and assembly costs due to the use of steel and the use of separately fastened parts.
One alternative method for making a gasket has been to extrude an expandable rubber sheet material and then calender or embed this material into a wire mesh, such as 21 gauge wire mesh material. The embedding process is performed by opposed rollers while the extruded, expandable rubber material is still soft from the extruded sheet production process. This produces a large roll of flat composite material which may then be die cut into gaskets or baffles. Due to the plastic deformability of the wire mesh material, these baffles may be bent for a particular application. Separate fastener elements are generally inserted through the formed gasket to allow it to be fastened to an automobile body. These wire mesh gaskets, however, have a tendency to remain flat due to the resilience of the rubber material. That is, the wire mesh may not be strong enough to retain certain bends in place, especially during shipping or storage. Also, as the product is a steel and rubber composite, the scrap produced during the die cutting process cannot be easily reclaimed or recycled since the expandable rubber material is not easily separated from the wire mesh and since the wire mesh will not melt back into the rubber material.
Another sealing product currently used in the automotive industry comprises a solid plastic plate overmolded with an expandable material. One disadvantage of this product is that the solid plates increase the weight of the product. Also, adherence of the expandable sealing material to the base support plate is a design concern.
To address various problems in the area of expandable gap filling products, such as those problems mentioned above and specifically experienced in the automotive and related industries, it would be desirable to provide an expandable gap filling product more efficiently manufactured for a wide variety of applications and more easily recycled or reclaimed.